<!doctype html> 
<html> 
<head> 
    <meta charset="utf-8"> 
    <title></title> 
</head>
<body>
<script type="text/javascript">

var a = alert;
var b = setInterval;
var c = setTimeout;
alert(a == alert);//true
alert(a(1));//1 undefined

</script>
</body>
</html>